How much does GPT-6 Luna cost on the API?

GPT-6 Luna costs $0.10 per 1M input tokens and $0.50 per 1M output tokens for prompts up to 272K tokens, with cached input at $0.01 per 1M and cache writes at $0.125 per 1M. Prompts longer than 272K tokens are billed at $0.20 input / $0.75 output per 1M, with cached input at $0.02.

How does GPT-6 Luna compare to GPT-5.6 Luna?

GPT-6 Luna costs half the input price of GPT-5.6 Luna ($0.10 vs $0.20 per 1M) but the same output price ($0.50 vs $1.20 — actually cheaper on output too). It represents the new generation's entry-level tier rather than a direct same-price replacement, so both remain listed.

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GPT-6 Luna

Name: GPT-6 Luna
Brand: OpenAI
Price: 0.10 USD
Availability: InStock

by OpenAI · GPT-6 family budget tier · released September 29, 2026 (DevDay)

The fastest, cheapest model in OpenAI's new GPT-6 family — the entry point below GPT-6.1 Sol and GPT-6 Astra.

Input $0.10 / 1M

Output $0.50 / 1M

Context 1M

Tier Budget

OpenAI Platform ↗ Updated October 7, 2026

§ API pricing

Per-token rates.

Input

$0.10/1M tokens

Prompt tokens (≤272K)

>272K tokens: $0.20 / 1M
Half GPT-5.6 Luna's input rate
Cached input $0.01 / 1M

Output

$0.50/1M tokens

Completion tokens (≤272K)

>272K tokens: $0.75 / 1M
Cheaper than GPT-5.6 Luna's $1.20 output
Fastest model in the GPT-6 family

Context

1Mtokens

Window

Same 1M window as GPT-6.1 Sol
High-volume, low-cost workloads
Released alongside GPT-6.1 Sol

Caching

$0.125cache write / 1M

Prompt caching

Cached input $0.01 / 1M (≤272K); $0.02 / 1M (>272K)
Cheapest cache rate OpenAI offers
Explicit cache breakpoints

GPT-6 Luna bills $0.10 / 1M input and $0.50 / 1M output for prompts up to 272K tokens; longer prompts are billed at $0.20 / $0.75 per 1M. Cached input reads are $0.01 / 1M (≤272K) or $0.02 / 1M (>272K).

What's new in GPT-6 Luna

OpenAI released GPT-6 Luna on September 29, 2026 at DevDay, alongside GPT-6.1 Sol and the new $500/mo ChatGPT Pro 500 tier. It's the budget entry point for the new GPT-6 generation, undercutting its predecessor GPT-5.6 Luna on both input and output price.

At $0.10 input / $0.50 output per 1M tokens (up to 272K tokens), Luna is OpenAI's cheapest current model. It's positioned for the same role GPT-5.6 Luna played: high-volume, latency-sensitive tasks where the GPT-6 family's other gains (quality, safety, tool use) still matter but Astra- or Sol-level reasoning doesn't.

Capabilities

Luna is built for speed and cost at scale rather than frontier reasoning. It's well suited to classification, extraction, short-form generation, and other well-defined, high-throughput tasks within the new GPT-6 family's safety and behavior improvements.

Typical use cases

High-volume classification and extraction
Chat triage and simple customer-support flows
Latency-sensitive, well-defined tasks
Cost-sensitive batch processing

Sibling and rival comparison

Model	Input / 1M	Output / 1M	Context
GPT-6 Luna	$0.10	$0.50	1M
GPT-6.1 Sol	$2	$10	1M
GPT-6 Astra	$10	$50	1.05M
GPT-5.6 Luna	$0.20	$1.20	1M
GPT-5.4 nano	$0.20	$1.25	400K

GPT-6 Luna undercuts every prior OpenAI budget model on price while matching the newer GPT-6 family's capability bump — half the input cost and well under half the output cost of GPT-5.6 Luna.

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